Ti valve modifications...

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perfconn
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Re: Ti valve modifications...

Post by perfconn » Tue Oct 10, 2017 1:53 pm

They don't have to be coated.I have run them for several seasons uncoated.

kosky racing
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Re: Ti valve modifications...

Post by kosky racing » Tue Oct 10, 2017 2:27 pm

The stem have to be coated several processes, used so as to not wear out the guide

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Re: Ti valve modifications...

Post by perfconn » Tue Oct 10, 2017 2:33 pm

Negative.The stems do not have to be coated.Out of several hundred sets of cup valves I have used none had the stems coated and only one set had the heads coated.The stems ride on a film of oil just like bearings do.Only stems I have seen coated were Manley.Never Del West or Exeldyne.

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Re: Ti valve modifications...

Post by m900 » Tue Oct 10, 2017 6:11 pm

I think the stems are always coated, ti is too sticky not to be. I can't remember the last time I saw a head that wasn't coated that came out of a cup engine. That said, I have cut down a lot of ti valves and never had one recoated. I have also put keeper grooves in the moly with no ill effects, though I suspect it is a no no.

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Re: Ti valve modifications...

Post by kosky racing » Tue Oct 10, 2017 6:36 pm

As far as I know all have some form of coating on the stems ,I have been using Ti valve for at least the last 40 some years and the stems have had some form of coating -moly -ti nitride- dlc-etc.MIKE

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Re: Ti valve modifications...

Post by carmakerevive » Tue Oct 10, 2017 8:19 pm

If the guides were steel or aluminium, it would be a problem. But being brass AND lubricated, i don't think coating is really necessitated
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Re: Ti valve modifications...

Post by PackardV8 » Tue Oct 10, 2017 9:57 pm

If the guides were steel or aluminium,
I've never seen a steel or aluminum valve guide. What engines come with those?
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Re: Ti valve modifications...

Post by Krooser » Tue Oct 10, 2017 10:54 pm

PackardV8 wrote:
Tue Oct 10, 2017 9:57 pm
If the guides were steel or aluminium,
I've never seen a steel or aluminum valve guide. What engines come with those?
I think he means a head without a removable guide. "STEEL" is a commonly use term for "cast iron" these days.
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Re: Ti valve modifications...

Post by roc » Wed Oct 11, 2017 12:04 am

Krooser wrote:
Tue Oct 10, 2017 10:54 pm
PackardV8 wrote:
Tue Oct 10, 2017 9:57 pm
If the guides were steel or aluminium,
I've never seen a steel or aluminum valve guide. What engines come with those?
I think he means a head without a removable guide. "STEEL" is a commonly use term for "cast iron" these days.
IF that's the case, that's very unfortunate given they're very different metals.

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Re: Ti valve modifications...

Post by MadBill » Wed Oct 11, 2017 12:25 am

Lots of folks speak of 'cement' floors, even though concrete is only ~ 1/6th to 1/7th cement solids.

FWIW, steel contains more iron than cast iron does.
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Re: Ti valve modifications...

Post by englertracing » Wed Oct 11, 2017 12:32 am

perfconn wrote:
Tue Oct 10, 2017 2:33 pm
Negative.The stems do not have to be coated.Out of several hundred sets of cup valves I have used none had the stems coated and only one set had the heads coated.The stems ride on a film of oil just like bearings do.Only stems I have seen coated were Manley.Never Del West or Exeldyne.
Every Del West or Exeldyne is coated with Chromium nitrite, on the stem and head, or chromium nitrite on the stem and titanium aluminum nitride on the head.

The Chromium nitrite looks just like shiny silver.

Molly coated stems and raw valve heads is old school.

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Re: Ti valve modifications...

Post by Warp Speed » Wed Oct 11, 2017 5:37 am

All titanium valves have coated stems. As was mentioned, they are typically either molly, crn or dlc ect.
Without this stem coating, excessive guide wear and failure are eminent.

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Re: Ti valve modifications...

Post by engineguyBill » Sat Oct 14, 2017 9:59 pm

MadBill wrote:
Wed Oct 11, 2017 12:25 am

FWIW, steel contains more iron than cast iron does.
Steel is iron with certain amounts of carbon added. Steel alloys have several other elements added for specific needs. For instance if the steel alloy contains at least 10 percent chromium, then it is described as stainless steel. Most stainless steel alloys however have somewhat more chromium, like 16 to 18 percent . . . . . Then there are are at least three major categories of stainless steel.

OP, remember - the Ti valves will need to have some sort of stem cap installed on the stem in order to insure their longivity.
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roc
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Re: Ti valve modifications...

Post by roc » Sat Oct 14, 2017 10:06 pm

engineguyBill wrote:
Sat Oct 14, 2017 9:59 pm
MadBill wrote:
Wed Oct 11, 2017 12:25 am

FWIW, steel contains more iron than cast iron does.
Steel is iron with certain amounts of carbon added. Steel alloys have several other elements added for specific needs. For instance if the steel alloy contains at least 10 percent chromium, then it is described as stainless steel. Most stainless steel alloys however have somewhat more chromium, like 16 to 18 percent . . . . . Then there are are at least three major categories of stainless steel.

OP, remember - the Ti valves will need to have some sort of stem cap installed on the stem in order to insure their longivity.
What Bill said! Both of them! =D>

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Re: Ti valve modifications...

Post by echosixmike » Sun Oct 15, 2017 1:23 am

For the OP, I've have dozens shortened by Jarvis Performance, wound up being about $10/valve. Mostly for BBM, so were 4.950, plus a lash cap. Seem to work OK so far.

https://www.facebook.com/jarvisperformance/

With the 7mm and larger stems, you may find hollow stem valves, which obviously can't be shortened. Kinda the risk of the game. I now have a 7 valve set of too long valves due to this discovery, lol. I think the exhausts are going to be solid, but I suppose they might be sodium filled or some awfulness. S/F....Ken M

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